


Experiments in Sanity

by holtz_gives_no_flux



Category: Ghostbusters (2016)
Genre: F/F, Oblivious Erin, and holtz is giving her filing system fits, erin is nothing if not a scientist, she likes things and people to fit into boxes, soft holtz
Language: English
Status: Completed
Published: 2017-08-15
Updated: 2017-09-02
Packaged: 2018-12-15 15:06:20
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,311
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11808459
Author URL: https://archiveofourown.org/users/holtz_gives_no_flux/pseuds/holtz_gives_no_flux
Summary: When Erin first met Holtz, she thought she should be institutionalized. Then she thought it was all an act. The truth is far more complicated and interesting than that.





	1. Chapter 1

**Author's Note:**

> idk what this is, my dude. I've been up for 29 hours and I'm listening to the Star Wars soundtrack. Time isn't real

When Erin came into the firehouse on a Sunday morning, she thought she was alone. Some college hooligans had moved in above her, and were trying (Erin could only assume unsuccessfully) to start a metal band. She had intended to get some work done on she and Abby's revised edition of their book in the comfort of her own home, but had decided after the new band's third song that the firehouse might be a better place to work. And really, she thought as she put the tea kettle on the stove, this was just as good as her apartment. Maybe even better. Her apartment was too neat, and up until now, too quiet without anyone in it. The firehouse had traffic noise and the gentle hum machines, and the large space never felt too big or lonely because it was filled with memories of the family that she had made for herself. 

She had settled in at her desk when she heard a faint tapping on the floor above her bringing her back from her new equations. She also heard very faint music coming from the hole that the fire pole went through. 

_ Is Holtzmann here? _ She thought, her brow furrowing. She was sure she would know if the 5 foot tall walking fire hazard were in the building. Now that she was paying attention, though, she couldn't  _ not _ notice it, so she got up and began cautiously walking up the stairs. She knew that Holtz had probably just left her stereo on, but always feared the worst when it came to a building full of paranormal research apparatus.

The sight that greeted her when she peeked around the corner into Holtzmann's lab, however, was stranger then she could have imagined. The music was jazz, turned down low. Holtz was there, all right, sitting somehow cross-legged on a bar stool behind her workbench, with a coffee balanced precariously on one knee and a book in her hands. 

The longer Erin stood there, the stranger the scene got. A moment passed, then a minute, and Holtz was... sitting still? Abby had warned her that Holtz was dangerous when she turned her music off, but she didn't look dangerous, she looked  _ relaxed _ . She seemed perfectly content to spend the afternoon reading. Her wardrobe looked less like she couldn't decide whether she wanted to anger or appease the gods of high fashion and more like it was just laundry day. She was wearing the MIT sweatshirt she had let Erin borrow when they first met over a sparkly shirt Erin was sure must have been Patty's with a pair of well-ripped purple jeans.

This was another outlier in the data from the experiment Erin had accidentally begun conducting. 

When Erin had first met Holtzmann, she was sure that there was no way that much crazy wasn't an act. Dr. Holtzmann was a highly renowned engineer who had taught and worked with some of the most esteemed organizations in her field - the field of designing and constructing machines based on the principles that Erin hypothesized about. She was actually surprised they hadn't met before. Surely Holtz could be a professional. The clothes and the hair and the words and the  _everything_ had to end  _somewhere._

It wasn't hard for Erin to test her theory. For most of her life, she had tried to be quiet and polite and to not take up too much space; she often walked into rooms unnoticed. It happened less now, but between her unwitting stealth and Holtzmann's tendency to hyperfocus, Erin could walk into the lab and Holtz would be turned around or welding or dancing and simply not notice her for ten minutes at a time.

During a career spent accidentally conducting this very experiment, Erin had found that there were two kinds of people in the world. There were people who were basically the same by themselves as they were in public, and those that were completely different. Phil, for instance, was the same. The things she saw him doing were normal things. Picking his nose, having fake arguments in the mirror, that sort of thing. Then there were people like Dr. Mitchell, who she had seen perform the Single Ladies dance in its entirety in his office during his lunch break. there was something fascinating about seeing who people were when they thought no one was looking.

Unfortunately, if there was one thing that Holtzmann was, it was a conundrum. At first, Erin was shocked to discover the crazy was  _real_. The list of things she had seen Holtzmann do when she thought she was alone included (but was by no means limited to) power sliding across the lab floor using a reactor fuel rod as a guitar, holding her breath until she passed out, performing the entire opening number of the Lion King with a chinchilla that she pulled from the front pocket of her overalls, having entire conversations on the phone in fake accents, setting up an entire class of animal crackers and giving them a physics lesson while taking questions, and starting many more fires than any self-respecting firehouse should have.

But there were also days like this. When she found Holtz doing something perfectly normal. She was slower, quieter, more serious. _Soft,_ Erin thought. Times when she gave whatever she was doing her undivided attention, unlike the projects she worked on during the day. Those got a manic, Doc Brown kind of attention, but she was always doing something else while she worked. She was dancing, she was eating, she was telling a joke about radiolytic decay that only Erin would laugh at. Erin thought she looked small. She  _was_ small, of course, but very rarely did she  _look_ small- her personality seemed to have a way of making up for how short she was.

Erin also noticed  _ other _ things about Holtz on the rare occasions like this when she had the chance to simply  _ look _ at her without it being too weird. Holtz was sexy. Every girl in the Tri-state area would tell you that. There was just something about the winks and the smirks and the way she carried herself that was obscenely attractive. Erin forgot sometimes, though, how classically beautiful Holtzmann was. The sharp, appraising gaze of electric blue eyes that knew exactly what they were looking at, the column of her neck, the blonde curls that were falling artfully out of her hairdo, which she kept pushing out of her face with the most graceful hands Erin had thought she had ever seen. She didn't know that she  _ should _ notice these things about her friend, but she didn't know that she could help it, either. And on a dreary Sunday morning with staccato rain tapping on the windows in contrast to the smooth notes coming from Holtzmann's record player, nothing seemed like it could be too dangerous.

From where Erin sat, Holtzmann was an enigma.  Even when she was stationary she seemed to be in motion, and she made feats of science look effortless and commonplace in the way she knew her machines so well that she blended in with them. She understood social convention well enough to ignore it completely except when it suited her in the form of a well placed wink or a pop culture reference. It was intoxicating. At first, Erin's observation was truly scientific.  She was sure the sheer amount of energy Holtz transferred from one system to another in any given minute must violate some fundamental law of the universe. She was sure there was no way someone could be in such a constant state of flux. Holtzmann was nothing like Erin’s boring steady state life. The difference in voltage between them was staggering. But the thing about voltage is that it seeks equilibrium. Whether it be in the bright, stinging shock of one of the hearse’s spark plugs or in the long drawn out trickle discharge of a wet lawn mower battery, potential always flowed from high to low. And that was what Erin was truly curious about. She didn't think there was any way the kind of wild energy that Holtzmann possessed was sustainable.  She had thought that sooner or later, it would get old. Erin would get used to it, or Holtz was bluffing and would stop putting so much energy into the manic facade she had created, but the quiet Holtz who possessed that calm, singular focus, much to Erin's confusion seemed to simply  _coexist_ with the Holtz that duct taped the head of a plastic horse onto the body of a troll doll while drunk and declared that she had invented the 'reverse-centaur'.

As if Holtz sitting still and being quiet wasn't strange enough, she appeared to be reading the owner's manual for a regular kitchen microwave. As Erin watched, Holtzmann's eyebrow quirked at the page she was reading. 

"Yup, need that." She mumbled, abruptly ripping out the page she was looking at and placing it on the bench in front of her, then continuing on.

Erin huffed a laugh from her place in the doorway, making Holtz look up at her, surprised but not startled to see her standing in the entrance to her lab.

"Morning, Erin." Holtz said calmly, smiling up at her. The smile and the easy use of her first name just added to Erin's confusion and raised a little heat into her cheeks.

"Hey Holtz." Erin said back, taking it all as invitation to come and lean on the workbench, where Holtz had evidently been ripping the pages out of user's guides and owner's manuals all morning.

"You're here early," Holtz stated, "Work doesn't start for... 22 more hours. That's a hell of a lot of overtime." 

Erin shrugged. "I have some work to do." 

Holtz rolled her eyes. "Erin." She began, "You  _ do _ know that that's what working hours are for, right?  _ Working? _ " As in, the rest of the hours are for  _ not  _ working?"

"Well, what about you?" Erin asked back, indignant. "Shouldn't you be... you know..." She gestured around, "out on the town? Or something?"

Holtz chuckled, grabbing the coffee off her knee and unfolding her legs.

"Erin, the only people who say 'out on the town' are people who desperately need a night out on the town."

"Whatever." Erin said, pretending to be put out. She rifled through the different pages Holtz had laid out. "What are all these?" She asked.

"Oh, just updating the ol' user's manual." Holtz replied, gathering the pages into a stack.

"The what?"

"The user's manual!" Holtz said again, pulling down a thick, metal bound binder covered in stickers from coffee shops and electronics stores from somewhere behind her and thumping it down onto the workbench, patting the cover affectionately. 

As Holtz went to go track down a hole punch downstairs, Erin fipped open the cover to the mess of pages inside.

Some of it was whole technical manuals for the equipment in the lab which Holtz had annotated, highlighted and added to as she had modified everything from the mass spectrometer to the TV. Other pages were beautifully drawn schematics for the machines Holtz had built herself; pages covered in math and scrawled but followable explanations of how the equipment worked. 

Her mouth must have fallen open because when Holtz returned and saw what she was looking at, she looked almost bashful. 

"What?" She asked defensively when Erin looked at her.

"Nothing, I don't know, I just never really figured you for the 'owner's guide' type, is all." Erin replied, shutting the book. Holtz grinned.

"Oh yeah, I love me a good manual." She said. "'Specially ones that have been translated from a different language. They're glorious. Absolute works of art." 

Erin laughed.

"I thought you would be more of a mad-science, shoot first read the directions later kind of person." She said.

"Stop, you're too sweet." Holtz said, "But in my experience, you have to  _know_ the rules before you, ya know, ignore them completely and build whatever you want. And like, somebody  _wrote_ this, you know?" she waved the page she had torn from the microwave manual out in front of her. "This cheap microwave is somebody's baby. If I want to turn it into a ghostubusting machine, I at least owe them the honor of reading how it was  _meant_ to be used. Plus, like power ratings and stuff. Those are important."

"Right, right." Erin nodded along, but she wasn't paying attention because she thought she had figured it out. This whole time she had been trying to prove that Holtz was either bonkers or faking it because if anything else was true, she had a completely different problem on her hands. If Holtz was  _both,_ if she was a perfect chocolate-vanilla swirl of the kind of person who was actively trying to build a lightsaber and the kind of person who sat quietly drinking coffee on a Sunday morning and reading microwave owners manuals out of respect for her fellow engineers, then she was something completely _new_. 

Erin knew was true it as soon as she thought it.

"Erin?"

Holtz was the most beautiful and interesting person Erin had ever met. 

"Errrrin?"

It was a crush. Erin had a crush. She didn't know what to do about it, but she knew it was there now, making her palms sweaty and her head spin.

"Erin!" Holtz yelled.

"Ahhh!" Erin yelled back, finally pulled from her thoughts and into the blue gaze of their subject.

"You ok?" Holtz asked

"Yeah, I just-" She began, but Holtz put her hands on her arms and was looking at her with genuine concern, and whatever grasp of the English language she had once held was disappearing rapidly. "I gotta go... downstairs."

"Sure." Holtz said, eyeing her suspiciously.

"And write."

"Uh-huh."

"Numbers"

"Right"

"And symbols. Little Greek symbols? Lots of those in physics."

"Of course."

Holtz looked at her suspiciously for one more long moment before letting go of her arms. Erin went downstairs and put her head in her hands. A crush. 

"Why me?" She asked to the ceiling, completely unaware that this crush would be the one to change her life.


	2. Chapter 2

**Notes for the Chapter:**

> kind of a short chapter, just wanted to get something out while i think about where this should go... wasn't planning on continuing, but im game if you guys are woot woot

_Tap._

_Tap._

_Tap._

It was Tuesday morning, and Erin was at her desk in the firehouse. There was a steaming mug of coffee beside her, she had her notebook and calculator out, and she was ready to work. Abby and Patty were there as well; Abby was scribbling away on some plans for a bust, and Patty was almost hidden behind stacks of books and papers in her corner of the first floor. Holtz was upstairs, every once in awhile changing the music or accidentally sending stray sparks through the fire pole hole, and showing her face every couple of hours for coffee, snacks, or just so everyone knew she was alive.

_Tap._

_Tap._

Erin was lost in thought. Her eyes were glazed over and she was slowly tapping her pencil on her grid-lined notebook and beginning to drive Abby absolutely insane.

She sighed.

 _It will go away eventually_ , she thought. At least, her crushes always had in the past; take Kevin, for instance. She had had a crush on him and now they were great friends. It happened all the time. He wasn't any less important to her, she just wasn't  _into_ him anymore. It wore off.

 _After you tried to make a move on him and he told you he had a boyfriend_. Erin thought.

But it would have to wear off. Holtz was a  _girl._ Sure, she was more of a  _dude_ than a lot of the guys Erin had dated; she recalled the first time she had seen Holtz in the garage working on the hearse, all grease marks and sweat and arms in a white tank top, standing somehow  _in_ the engine bay, trying to muscle over a giant socket wrench and looking like July in some middle aged woman's calendar. She had just hit so many of the  _dude_ wickets that had Erin not been busy checking her out, she would have laughed out loud. 

But the fact remained that Holtz was decidedly and tragically a woman. And Erin Gilbert did not date women. Not anymore, anyway. She had decided a long time ago that she was going to be normal, and that meant a job at Columbia, no more believing in ghosts, and no dating women. The only person who even knew she was bisexual was Abby, after a tearful confession in college, and she was sworn to absolute secrecy. This little crush she had on Holtz would go away eventually, and no one would ever be the wiser.

Of course, looking back on it, she had lost the job at Columbia and was actively believing in and researching ghosts, and those were two of the best things to ever happen to her. Maybe it wouldn't actually be so bad if she just-

"Erin!" Abby snapped, startling her before her thoughts made it any farther down that path. "Could ya cool it? With the pen?"

"Oh!" Erin said, looking down and realizing what she had been doing. "Sure."

She looked back down at her notebook and got back to work. Energy-mass equivalence. Mass defect. Pair production and annihilation. She was trying to figure out a way to stabilize the energy released when matter and antimatter collided into something usable. She wasn't sure if she could, but she was pretty sure, and it gave her a chance to use her favorite equation. Einstein's equation was often abbreviated into E=mc2, but that wasn't the whole story and it drove Erin nuts that people always wrote it like that without understanding where it came from.

_Tap._

_Tap._

She didn't really know why it was her favorite, something about matter just springing into energy and back again was fascinating. Plus it was such a widely recognized equation that it was cool to know how it was actually meant to be used.

Holtzmann's favorite equation was the shielding equation. She liked it because she liked to know whether or not she was going to die, and how much lead she needed to scrounge or buy in order to keep radiation and ghosts from getting out of her machines, but mostly because she liked to say 'flux'. The jokes were endless. 'How much shielding until I don't give a flux?'. 'If you walk in there, you're gonna go flux yourself'. 'Hey baby, wanna flux?'. It never stopped. Even the symbol was her favorite. 'So easy to draw, and yet no one will have a clue what it means.' Holtz had said. What a dork. Who has a favorite  _symbol_? 

_Tap._

_Tap._

Holtz was the only person not to look at her like she had three heads when she mentioned having a favorite equation. Erin was just about to write it up, but Holtz beat her to it. "Yeah, that one. It's my favorite." Erin said. Holtz didn't even bat an eyelash. "Oh, yeah, energy-mass equivalence, that's a good one. I like shielding though. Hehe.  _flux_." and that was the end of it, Erin thought, smiling.

"ERIN." Abby yelled.

"Sorry!" Erin yelled back.

"Go annoy Holtzmann or something! You're driving me bonkers!"

"Fine," Erin mumbled, "I can't remember Planck's constant anyway. She'll know." 

She picked up her notebook and headed for the stairs to the lab.

"Holtz! Put your pants on, I'm coming upstairs!" She called, before disappearing around the corner.

 

**Notes for the Chapter:**

> It kind of sounds like abbys being mean? idk, she's not, i just couldnt quite get the voice right. Also, i think Erin's bi. you can think whatcha want, but that's how im gonna write her :) I might develop that whole backstory later, idk. tell me what you guys think. I dont know why i wrote for so long about equations, but it happened. I make no apologies.


	3. Chapter 3

**Notes for the Chapter:**

> sorry its been awhile, work is hell. Thanks for the reading and the feedback, though, you guys are gr8 :)
> 
> This chapter has a TW for self-harm 
> 
> Nothing explicit, its just hinted at, but its in there. We're hanging a soft left into angst-ville.

There was flickering light and crackling electricity coming from the lab that grew louder as Erin ascended the stairs. She plopped her things down on the desk in her corner of the room and looked over to Holtzmann's workbench, where all that could be seen of her were two giant gloves and a faceless welding helmet.

Erin made her way over, squinting her eyes against the light from the welding torch.

"Holtz!" She yelled over the noise. 

The welding helmet looked up and cocked its head like a puppy who had just heard its name, then a giant gloved hand waved excitedly at her. The helmet looked at Erin, then at the torch, then back to Erin, finally setting the torch down and pulling the helmet off, unleashing an avalanche of blonde curls and a grinning Holtzmann. 

"Dr. Erin Gilbert, PhD." Holtz stated, holding out her hand as if they had never met, "What a pleasant surprise. So nice to finally meet you in person."

"Holtz, its only been an hour since the last time you saw me." Erin said.

"Ah, potatoes-tomatoes, Gilbert. What do you need?"

"What? Who says I need anything? Maybe I just wanted to work up here for awhile." Erin said, crossing her arms defensively.

"That not what your face says," Holtz said.

"My... my face?" Erin asked, confused.

"Oh yes, Erin, you have a very loud face. A face that says you came up here to ask me something that you could very easily Google. Either that, or Abby banished you again." She said, grinning.

They looked at each other for a long moment, Erin defiant, Holtz expectant. She didn't always let on, but Holtz was deceptively perceptive. As much as she tried to distance herself from the real world, she did understand it. It was one of the things that Erin found so interesting about her.

As much as Erin hated to admit it, Holtz had guessed exactly right. Her shoulders deflated, knowing she'd been had.

"I need Planck's constant." Erin mumbled.

"YES! I knew it!" Holtz yelled, triumphant.

" _And_ Abby kicked me out." She added

"Ah, banish-ed! 2 for 1 sale, wonderful." Holtz said, clapping her hands together. "Planck's constant is 6.626 x 10-34, by the way." Holtz said, winking at her.

"Thanks." Erin said, going back to her side of the room. She set up her work on the white board as Holtz put her helmet and gloves back on.

Now that all her numbers were in a row, she found it easy to jump back into her work, barely even registering the sounds of Holtz working behind her. There was welding, grinding, banging, "owee!", more grinding...

"Oh, shit."

Then nothing.

It wasn't until Erin turned around to ask Holtz a question a moment later that she realized why all the noise had stopped.

"Hey, Holtz- Oh my god!" Erin exclaimed.

Holtz had blood all over her, and was duct taping a paper towel over a gash across the back of her wrist. There was even blood on her face from where she had wiped her forehead.

"What did you do?!" 

"It wasn't me! I just caught it on some sheet metal, it didn't even hurt!"

"What? No, Holtz, stop it!" Erin said, taking away the tape, "Duct tape is  _not_ for first aid! We've been over this!"

"It's fine!" Holtz replied, but it obviously wasn't; the paper towels were already mostly saturated.

"Oh my god, Holtz, come here." Erin said, pulling Holtz along behind her by her good hand to the bathroom. "Sit up on the sink."

"Yes, mom." Holtz replied, hopping up on the counter and swinging her feet, tightening a fitting on the faucet while she waited for Erin to find a first aid kit and run the hot water.

Erin took Holtzmann's hand very gently and moved it to look at the wound. Holtz hissed as Erin cleaned it as carefully as she could with a warm washcloth. 

She wasn't sure she had ever been this close to Holtzmann for this long. It wasn't weird or terrifying or any of the things she thought it might be. Especially not now, when there were other things to worry about. It was surprisingly easy. Holtzmann's hand was warm and the skin on the palm was rough, but her fingers were long and thin. Her skin was covered in tiny nicks and cuts of all different shapes and states of healing. There were tiny burn marks on her arms from welding slag, her knuckles were scuffed and bruised from hitting them when a tight bolt finally came loose, and there were thin scratches from the sheet metal of the proton packs.

There were a few light scars, too. One was definitely a burn, (Erin had been there for it, right after they had saved the city) one was jagged, one was a surgical scar from where she had broken her arm back when it was just her and Abby at Higgins, one had a dark mark that looked like it might have been a pencil stick. There was a curious one too, up by her elbow, that was just two straight white lines crossed in an x. Erin tried to think of how they could have happened, but couldn't come up with any tool that would explain them. They were old and faded, but they looked deep, and as Erin cleaned and bandaged Holtz back up, she reached up and ran two fingers over the x.

Holtz, who had been humming the Jurassic Park theme song and barely paying attention to what Erin was doing jumped about a mile, pulling her arm back like she had been burned.  

"Sorry!" Erin said, almost missing the flash of confusion and panic in Holtzmann's eyes. 

 _Almost_.

But it was gone in an instant; well before Erin had time to comment on it, and Holtz was back.

"You gotta be careful with the band-aids, there, Gilbert." Holtz joked, not quite able to put all of the ease back into her voice but clearly not about to acknowledge her reaction, either. 

"Sorry, Holtz." Erin said again, confused and curious, but not about to ask about it.

She finished applying the bandage and sent Holtz on her way.

Holtz hopped off the counter and bounced back over to her work, content to act like nothing happened.

 

 

**Notes for the Chapter:**

> ughghghg i hate these short chapters. i keep meaning to write more but also sleep is important so this is all you get for today.   
> On the self harm thing - basically the idea is holtz used to hurt herself to bring herself back when she would dissociate without realizing that it might be a symptom of a bigger problem, until she cuts deep enough to scar and someone notices and she gets some help. i know self harm is an important and heavy subject and i dont want to use it as a gimmick or make it unbelieveable, but i think it fits. but hold me accountable, lemme know if theres anything you dont agree with or think should be changed.

**Author's Note:**

> hit like and subscribe


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